If I'm not mistaken the Blaster is used as an updater, long before the MIGHTY ix1.4 FW there were many updates and the blaster made these updates a breeze as you only had to open your xbox case once to install it and after that any update could be done via the, now thanks to the Blaster, external SATA port(it also has a convenient modeB switch so no need for slax).
As for X360 USB, I have never heard of anyone using this for flashing a drive. I believe that is the opposite of what you want.
I SUGGEST...Connectivity Kit V2 (generic but the same) - $16
This will adapt the xbox stlye power plug into a regular old 4pin equipped with eject and modeB buttons
Long SATA cable - $5
This is so you don't have to set the drive right next to the computer, with this SATA cable you got A LOT of play to move about.
External Power Supply (4pin power plug) - $6
This is to plug into the connectivity piece for power. You don't want to use your PC to power it because when you need to power off and on (BenQ, Samsung) it makes it drastically easier.
Grand Total=$27 shipped
Hope that Helped